A Stirling engine has been known in the past. The Stirling engine includes a heat exchange unit for hot energy and a heat exchange unit for cold energy. Hot energy is supplied to the heat exchange unit for hot energy and cold energy is supplied to the heat exchange for cold energy, whereby the Stirling engine obtains power.
A technology is known for vaporizing liquid while recovering power by adopting cold energy (latent heat) of the liquid as the cold energy supplied to the Stirling engine of this type (e.g., Patent Document 1). In other words, the Stirling engine according to Patent Document 1 vaporizes liquid (LNG: liquefied natural gas) while recovering power by applying the heat of vaporization to the liquid.
Specifically, a Stirling engine 102 of Patent Document 1 includes, as shown in FIG. 7, a cooler 104 provided on the outer side of a head (a heat exchange unit for cold energy) of a displacer cylinder 106 of the Stirling engine 102. The cooler 104 cools the head of the displacer cylinder 106 with the latent heat of the LNG supplied to the inside of the cooler 104. As a result of the cooling, the LNG from which the latent heat is transferred (to which the heat of vaporization is applied) vaporizes.
However, in the Stirling engine 102 of Patent Document 1, complicated processing is necessary in order to obtain target gas from the liquid (LNG) at high efficiency. Specifically, the Stirling engine 102 of Patent Document 1 is configured to immerse the head of the Displacer cylinder 106 in the liquid stored in the cooler 104 in order to bring the liquid into contact with the displacer cylinder 106. Therefore, gas already vaporized and gas not vaporized yet are separated. In order to obtain target gas at high efficiency in a state in which the liquid and the gas are separated in this way, as shown in FIG. 7, it is necessary to separately collect the gas and the liquid from the cooler 104, keep a state in which the gas is heated and vaporized by a heater 105a and vaporize the liquid with a vaporizer 105b, and mix the gas from the heater 105a and the vaporizer 105b with a mixer 115.
Therefore, in order to obtain target gas at high efficiency using the Stirling engine 102 of Patent Document 1, there is a problem in that a process and equipment therefor are complicated.
Patent Document 1: Japanese Patent Application Laid-Open No. H11-22550